可逆式資訊隱藏方法使用影像內插技術與機密訊息縮減策略

Reversible Data Hiding Based on Image Interpolation with the Use of Secret Message Reduction Strategy

林美辰(Mei-Chen Lin)

指導教授 ： 呂慈純

朝陽科技大學/資訊學院/資訊管理系/碩士(2015年)

摘要

近年來，資訊隱藏相關技術研究蓬勃發展，使用方法也日新月異，目前最常被提及的技術有直方圖位移技術和差異擴張技術等方法。在各種藏入方法中影像放大策略，也是很常被使用到的技術。影像放大技術主要是將影像透過公式將原始影像變成數倍大，再將機密訊息嵌入於放大的部份。然而，影像在放大過程，影像品質已受到破壞，若再加上嵌入機密訊息的失真，其影像品質將受到很大的考驗。因此如何在一定的影像品質條件下，嵌入最多的機密訊息是學者們討論的重點。2012年Lee等學者提出一個以鄰近像素為基底之內插放大技術，並將機密訊息藏於放大後之內插像素中。該方法能有效預測出相鄰二像素中間之像素值，使得機密訊息在藏入後不致於失真太多。然而，本研究發現雖然Lee等學者的鄰近像素預測方法可順利取得預測值，但因為嵌入的機密訊息大小不一，當機密訊息較大時，藏入預測值中，就會造成失真較大。因此，如何將機密訊息先做處理，以減少因藏入而造成的損害，即是本論文的目的。本論文提出一個機密訊息縮減策略，將機密訊息從值域範圍皆為正數，變成有正值、有負值的值域範圍，讓機密訊息變小，以達到減小偽裝影像失真度的目標。

關鍵字

機密訊息縮減策略 ； 相鄰像素插值法 ； 影像放大技術

並列摘要

In recent years, data hiding research has developed at an exponential rate. At present, the most commonly mentioned techniques are histogram-shift based and difference expansion. Among the methods, image enlargement strategy is a commonly used technique. Image enlargement technique multiplies the original image by using a formula, and then embeds secret messages in the enlarged part. However, the image quality will be severely tested because of quality damage in the enlargement process, together with distortion of embedded secret messages. Therefore, how to embed as many secret messages as possible under certain image quality conditions remains an academic focus. In 2012 Lee et al. proposed an interpolation enlargement technique with neighboring pixels as the base to embed secret messages in enlarged interpolated pixels. This method can effectively predict the pixel between two adjacent pixels so as to reduce distortion of hidden secret messages. However, this study found that the neighboring pixel prediction method of Lee et al. can successfully achieve a predictive value, but different sizes of embedded secret messages will cause great distortion when a large secret message is hidden in the predicted value. Therefore, how to deal with the secret messages in advance to reduce the harm caused by embedding is the purpose of this thesis. A secret message reduction strategy proposed in this thesis changes positive secret messages to positive and negative ones to decrease the values and thereby reduce the stego-image distortion.

並列關鍵字

ecret message reduction strategy ； interpolation by neighboring pixels ； enlarge image technology

參考文獻

[13]J. Wen, J. Lei and Y. Wan(2012), “Reversible Data Hiding Through Adaptive Prediction and Prediction Error Histogram Modification,” International Journal of Fuzzy Systems, Vol. 14, No. 2, pp. 244-256.

[1]A. M. Alattar(2004), “Reversible Watermark Using the Difference Expansion of a Generalized Integer Transform,” IEEE Transactions on Image Processing, Vol. 13, pp. 1147-1156.

[2]X. Gui, X. Li, and B. Yang(2014), “A High Capacity Reversible Data Hiding Scheme Based on Generalized Prediction –Error Expansion and Adaptive Embedding,” Signal Processing, Vol. 98, pp. 370-380.

[3]K. H. Jung and K. Y. Yoo(2009), “Data Hiding Method Using Image Interpolation,” Computer Standards & Interfaces, Vol. 31, No. 2, pp. 465-470.

[4]C. F. Lee and Y. L. Huang(2012), “An Efficient Image Interpolation Increasing Payload in Reversible Data Hiding,” Expert Systems with Applications, Vol. 39, No. 8, pp. 6712-6719.